diff --git a/modules/imgproc/src/filter.cpp b/modules/imgproc/src/filter.cpp
index e51986c394..d23de91ea1 100644
--- a/modules/imgproc/src/filter.cpp
+++ b/modules/imgproc/src/filter.cpp
@@ -3492,7 +3492,7 @@ static bool ocl_sepFilter2D_SinglePass(InputArray _src, OutputArray _dst,
         return false;
 
     size_t lt2[2] = { optimizedSepFilterLocalSize, optimizedSepFilterLocalSize };
-    size_t gt2[2] = { lt2[0] * (1 + (size.width - 1) / lt2[0]), lt2[1] * (1 + (size.height - 1) / lt2[1]) };
+    size_t gt2[2] = { lt2[0] * (1 + (size.width - 1) / lt2[0]), optimizedSepFilterLocalSize};
 
     char cvt[2][40];
     const char * const borderMap[] = { "BORDER_CONSTANT", "BORDER_REPLICATE", "BORDER_REFLECT", "BORDER_WRAP",
diff --git a/modules/imgproc/src/opencl/filterSep_singlePass.cl b/modules/imgproc/src/opencl/filterSep_singlePass.cl
index 3952577d77..6c3bbdc161 100644
--- a/modules/imgproc/src/opencl/filterSep_singlePass.cl
+++ b/modules/imgproc/src/opencl/filterSep_singlePass.cl
@@ -119,17 +119,15 @@ __kernel void sep_filter(__global uchar* Src, int src_step, int srcOffsetX, int
     int liy = get_local_id(1);
 
     int x = get_global_id(0);
-    int y = get_global_id(1);
 
     // calculate pixel position in source image taking image offset into account
     int srcX = x + srcOffsetX - RADIUSX;
-    int srcY = y + srcOffsetY - RADIUSY;
 
     // extrapolate coordinates, if needed
     // and read my own source pixel into local memory
     // with account for extra border pixels, which will be read by starting workitems
     int clocY = liy;
-    int cSrcY = srcY;
+    int cSrcY = liy + srcOffsetY - RADIUSY;
     do
     {
         int yb = cSrcY;
@@ -154,48 +152,76 @@ __kernel void sep_filter(__global uchar* Src, int src_step, int srcOffsetX, int
     while (clocY < BLK_Y+(RADIUSY*2));
     barrier(CLK_LOCAL_MEM_FENCE);
 
-    // do vertical filter pass
-    // and store intermediate results to second local memory array
-    int i, clocX = lix;
-    WT sum = (WT) 0;
-    do
+    for (int y = 0; y < dst_rows; y+=BLK_Y)
     {
-        sum = (WT) 0;
-        for (i=0; i<=2*RADIUSY; i++)
+        // do vertical filter pass
+        // and store intermediate results to second local memory array
+        int i, clocX = lix;
+        WT sum = (WT) 0;
+        do
+        {
+            sum = (WT) 0;
+            for (i=0; i<=2*RADIUSY; i++)
 #if (defined(INTEGER_ARITHMETIC) && !INTEL_DEVICE)
-            sum = mad24(lsmem[liy+i][clocX], mat_kernelY[i], sum);
+                sum = mad24(lsmem[liy + i][clocX], mat_kernelY[i], sum);
 #else
-            sum = mad(lsmem[liy+i][clocX], mat_kernelY[i], sum);
+                sum = mad(lsmem[liy + i][clocX], mat_kernelY[i], sum);
 #endif
-        lsmemDy[liy][clocX] = sum;
-        clocX += BLK_X;
-    }
-    while(clocX < BLK_X+(RADIUSX*2));
-    barrier(CLK_LOCAL_MEM_FENCE);
+            lsmemDy[liy][clocX] = sum;
+            clocX += BLK_X;
+        }
+        while(clocX < BLK_X+(RADIUSX*2));
+        barrier(CLK_LOCAL_MEM_FENCE);
 
-    // if this pixel happened to be out of image borders because of global size rounding,
-    // then just return
-    if( x >= dst_cols || y >=dst_rows )
-        return;
-
-    // do second horizontal filter pass
-    // and calculate final result
-    sum = 0.0f;
-    for (i=0; i<=2*RADIUSX; i++)
+        // if this pixel happened to be out of image borders because of global size rounding,
+        // then just return
+        if ((x < dst_cols) && (y + liy < dst_rows))
+        {
+            // do second horizontal filter pass
+            // and calculate final result
+            sum = 0.0f;
+            for (i=0; i<=2*RADIUSX; i++)
 #if (defined(INTEGER_ARITHMETIC) && !INTEL_DEVICE)
-        sum = mad24(lsmemDy[liy][lix+i], mat_kernelX[i], sum);
+                sum = mad24(lsmemDy[liy][lix+i], mat_kernelX[i], sum);
 #else
-        sum = mad(lsmemDy[liy][lix+i], mat_kernelX[i], sum);
+                sum = mad(lsmemDy[liy][lix+i], mat_kernelX[i], sum);
 #endif
 
 #ifdef INTEGER_ARITHMETIC
 #ifdef INTEL_DEVICE
-    sum = (sum + (1 << (SHIFT_BITS-1))) / (1 << SHIFT_BITS);
+            sum = (sum + (1 << (SHIFT_BITS-1))) / (1 << SHIFT_BITS);
 #else
-    sum = (sum + (1 << (SHIFT_BITS-1))) >> SHIFT_BITS;
+            sum = (sum + (1 << (SHIFT_BITS-1))) >> SHIFT_BITS;
 #endif
 #endif
+            // store result into destination image
+            storepix(convertToDstT(sum + (WT)(delta)), Dst + mad24(y + liy, dst_step, mad24(x, DSTSIZE, dst_offset)));
+        }
+
+        for (int i = liy * BLK_X + lix; i < (RADIUSY*2) * (BLK_X+(RADIUSX*2)); i += BLK_X * BLK_Y)
+        {
+            int clocX = i % (BLK_X+(RADIUSX*2));
+            int clocY = i / (BLK_X+(RADIUSX*2));
+            lsmem[clocY][clocX] = lsmem[clocY + BLK_Y][clocX];
+        }
+        barrier(CLK_LOCAL_MEM_FENCE);
+
+        int cSrcY = y + BLK_Y + liy + srcOffsetY + RADIUSY;
+        EXTRAPOLATE(cSrcY, (height));
+
+        clocX = lix;
+        int cSrcX = x + srcOffsetX - RADIUSX;
+        do
+        {
+            int xb = cSrcX;
+            EXTRAPOLATE(xb,(width));
+            lsmem[liy + 2*RADIUSY][clocX] = ELEM(xb, cSrcY, (width), (height), 0 );
+
+            clocX += BLK_X;
+            cSrcX += BLK_X;
+        }
+        while(clocX < BLK_X+(RADIUSX*2));
+        barrier(CLK_LOCAL_MEM_FENCE);
+    }
 
-    // store result into destination image
-    storepix(convertToDstT(sum + (WT)(delta)), Dst + mad24(y, dst_step, mad24(x, DSTSIZE, dst_offset)));
 }